Deep Rolling Head

ABSTRACT

The invention relates to a burnishing roller head ( 10 ) for burnishing radii ( 28 ) or recesses which respectively laterally define the bearing seats of main and lifting journals ( 3, 4 ) of crankshafts ( 1 ) for motors of motor vehicles. Two disk-shaped and cylindrical burnishing rollers ( 11, 12 ) with the same diameter and approximately the same width are arranged parallel and at a mutual distance from each other in the housing ( 9 ) of the burnishing roller head ( 10 ) and are mounted in such a way that they can rotate about a common horizontal rotational axis ( 18 ) in the housing ( 9 ) of the burnishing roller head ( 10 ). Said burnishing rollers ( 11, 12 ) respectively comprise, on the outer peripheral edges ( 22 ) thereof opposing each other, a rotating rounded projection ( 21 ) which enlarges the diameter of the respective burnishing roller ( 11, 12 ) by a pre-determined measure ( 24 ), the axial width of the burnishing roller ( 11, 12 ) extending simultaneously over a section of the projection close to the edge.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Stage of International Application No. PCT/EP2004/013824, filed Dec. 4, 2004. The disclosure of the above application is incorporated hereby by reference.

FIELD

The invention concerned is a deep rolling head used for deep rolling radii and recesses that limit the bearing seat—on the side—for main pins and crankpins on crankshafts for motors in vehicles.

BACKGROUND

The deep rolling head is especially intended for deep rolling split pin crankpins on crankshafts. Deep rolling becomes difficult with split pin crankpins at the fillet. The fillet adjoins both adjacent crankpins on a crankshaft. The deep rolling tool is supported only on one side by a section of the circumference and on both sides at the following section, i.e. the fillet, when rolling above the circumference of this type of split pin crankpin. The deep rolling head is not only limited to deep rolling split pin crankpins. It has also been designed for deep rolling common main pins and crankpins on crankshafts that are limited on both sides by radii and recesses.

For example, a deep rolling unit for deep rolling crankshafts is known from U.S. Pat. No. 5,445,003 that is able to deep roll split pin crankpins. It is equipped with two deep rolling heads that support one another. They have work rollers only on their opposite sides. This known deep rolling unit can only be used for deep rolling the exterior radii or recesses of the crankpin. This means, that the fillet cannot be machined.

SUMMARY

Therefore, there is a need for the invention described in this document. The invention is intended for deep rolling radii or recesses of all types of main pins or crankpins on crankshafts. In particular, the invention is intended for deep rolling fillets of split pin crankpins, which was not possible to do before using previous deep rolling tools.

The invention concerns a deep rolling head having two disc- or ring-shaped and cylindrical work rollers with the same external diameter and almost similar axial width parallel and at a mutual distance from one another in the housing (9) of the deep rolling head and mounted so that they can rotate at a common, horizontal rotational axis in the housing of the deep rolling head, and having a protrusion on their opposite borders that is peripheral, rounded off, and increases the external diameter of each work roller by a specified size, which also simultaneously extends beyond the section—near to the edge—of the axial width of the work roller. Therefore, the borders are designed to engage in the depressions of the recesses that are already present when deep rolling recesses; or to roll a depression in the radii when deep rolling radii on transitions. When engaging or rolling with the section, the work roller supports its axial width on the bearing seat. During this, the deep rolling head is stabilised by itself since deep rolling split pin crankpins over the border section of the area of the bearing seat that is not bordering the fillet either engages in a depression on the opposite edge of the bearing seat or creates a depression when deep rolling radii in which it is simultaneously placed on the side. In this case, deep rolling heads cannot be simultaneously supported as stated earlier. Due to the geometric ratios, two deep rolling heads cannot work next to one another for the crankpins of a split pin crankshaft that are adjacent and only adjoined by the fillet. For this reason, it is beneficial to align the two deep rolling heads at an axial distance from one another. This allows the deep rolling forces to be taken up by supporting rollers that lie opposite to the deep rolling heads. The deep rolling tool consists of a deep rolling head and a support roller head.

The axial width of the deep rolling head with both its disc-shaped work rollers corresponds to the maximum width of the bearing seat from oil collar to oil collar. A limited, axial resilience of both work rollers can be beneficial when adjusting to the production tolerances of the bearing seat. The design of the deep rolling head is more beneficial when one of the two discs making up the work rollers has a protruding ring flange on one side, while the other disc has a protruding, cylindrical pin that are both concentrically aligned to the common rotational axis of both work rollers. In particular, the cylindrical pin in the assembled deep rolling head of one work roller should engage almost free of play into the ring flange of the other work roller. Both work rollers can be adjoined with screws or pins to allow for later detachment, or they can be permanently adjoined with riveting. By connecting the two work rollers at their centres, a steady assembly can be made which can be easily stored in the housing of the deep rolling head. The assembly is between the exterior circumference of the ring flange and the housing of the deep rolling head. This creates a partner arrangement comparable with twin rollers used for buggies (pram). Both plain bearings and rolling bearings are suitable for use.

Alternatively, the deep rolling head can be designed by forming both work rollers out of ring discs which are placed on the pins that protrude out of the wall of the housing of the deep rolling head. With this design, the ring discs can be mounted to the bearing pin with simple, known means so that they are free to rotate.

The work rollers are made of a high-strength, and in particular, tempered material as is generally the case when using common work rollers. If a plain bearing is used for the work roller, the housing of the deep rolling head or the part of the housing in which the work roller is stored must be made of bronze. Both work rollers of a deep rolling head will hereinafter be referred to as exterior roller when alluding to the main journal pin and as interior work roller when placed at the adjacent crankpins of a split pin crankshaft.

The deep rolling head can be used as follows when deep rolling split pin crankpins:

1st Case: Two exterior and one interior recesses are present on split pin crankpins of a split pin crankshaft which limit the two adjacent bearing seats of the split pin crankpin on both sides. The exterior recesses are first deep rolled by two deep rolling heads that support each other, as previously stated in U.S. Pat. No. 5,445,003. The deep rolling direction with the known deep rolling heads, e.g. at a 35° angle to the crankshaft axis, is beneficial since a specified resistance to fatigue can be reached.

In the current case, the exterior work roller of the invention-related deep rolling head only has guiding properties and does not carry out any deep rolling procedure in the fillet. The exterior curvature radius of the exterior work roller does not touch the recess in the fillet of the bearing seat. In addition, the external diameter of the exterior work roller is reduced by at least the engaging depth of the interior work roller while deep rolling the fillet and by the corresponding tolerances of the interior depression when prefabricating the crankshaft. The exterior work roller rests in the exterior recess in the remaining circumference section of the split pin crankpin and ensures that the deep rolling head maintains its correct, axial position. In this circumference section of the intervention of the exterior work roller, the deep rolling force acting on the deep rolling head is reduced. While this is taking place, a suitable deep rolling force, e.g. 10 kN, is being built up in the fillet.

2nd Case: Interior and exterior recesses are present on the split pin crankpins of the crankshaft. They limit the bearing seat on the side. These recesses are deep rolled simultaneously with the deep rolling head. In addition to this, the deep rolling force is increased via the circumference section of the bearing seat where the fillet is, e.g. doubled. The split pin crankshaft must be prefabricated as precisely as possible since a deep rolling unit can only balance out the difference in depth of the recesses to a minimum.

The external diameters of the two work rollers are the same size in this case. The following describes the tool with a design example.

DRAWINGS

The following figures are schematic and not to scale.

FIG. 1 Perspective figure of a section of a split pin crankshaft.

FIG. 2 Side view of a deep rolling head.

FIG. 3 A cross-section of the deep rolling head displayed in FIG. 2 III-III divided along line III-III.

FIG. 4 A few individual parts of the deep rolling head.

FIG. 5 The situation before deep rolling radii on a split pin crankpin.

FIG. 6 The situation like in FIG. 5 with two installed deep rolling heads.

FIG. 7 Deep rolling details.

DETAILED DESCRIPTION

The split pin crankshaft 1 of FIG. 1 has a split pin crankpin 2 with the two individual crankpins 3 and 4 which are connected to each other by a fillet 5, illustrated by the curly arrow. The two crankpins 3 and 4 are both limited on the side by webs 7 and 8. This forms the transitions as recess 6 between the crankpin 4 and the web 8. FIG. 1 portrays the ratios on a split pin crankshaft 1.

Two disc-shaped work rollers 11 and 12 are mounted so that they can rotate around a common rotational axis 13 in the housing 9 of a deep rolling head. The cylindrical disc of the work roller 12 has a protruding ring flange 15 on one side 14 which has been placed concentrically to the rotational axis 13. A protruding cylindrical pin 17 on the opposing side 16 of the cylindrical disc of the work roller 11 corresponds to the ring flange 15. The pin is also concentrically aligned to the common rotational axis 13. The cylindrical pin 17 engages inside the cylindrical flange in the assembled deep rolling head 10, as seen in FIG. 3. The pin engages with very little play. The work rollers 11 and 12 that are brought together in this way are to be joined together with screws 18.

A plain bearing is located between the work roller 11 and 12 and the housing 9 of the deep rolling head 10 in the current design example. The housing 9 is made of bronze and has a bore 19. The ring flange 15 engages in the bore 19 with its exterior side 35.

As is already known, the crankpin 4 is supported by the supporting rollers 20 when deep rolling the crankpin 4 as it is seen in FIGS. 2 and 3. Two supporting rollers 20 are united in a support roller head. The deep rolling head and the support roller head make up the deep rolling unit.

The protrusion 21 in FIG. 4 indicates the design of the borders 22 of both work rollers 11 and 12. The borders 22 of both work rollers 11 and 12 are identical in their design.

FIG. 5 shows the situation of deep rolling two crankpins 3 and 4 with two deep rolling heads 10 and 23 which are both identical in design. The outside border 22 of the work roller 12 is rounded off and enlarges the external diameter of each disc of the respective work roller 11 and 12 by a specified size 24. The border 22 also extends beyond a section 25—which is on the edge—of an axial width of each work roller 11 and 12. In the current design example, both work rollers 11 and 12 have the same axial width. This is not necessarily required. Different widths are also possible. The total width of a deep rolling head 10 or 23 spans from the oil collar 26 of a crankpin 3 or 4 to the oil collar 31 of the fillet 5. The exterior recesses 29 are intended to be transitions between the crankpin 3 or 4 to the respective webs 27 via the oil collar 26. The borders 22 of the work rollers 11 and 12 engage in the exterior recesses 29 of the crankpins 3 and 4 while deep rolling. The size 24 is reduced to the value 0, i.e. on the predominant section of their axial width, the work rollers 11 and 12 support themselves on the bearing seats 36 of the respective crankpins 3 or 4 as is seen in FIG. 5. The borders 22 of the exterior work rollers 12 that engage in the exterior recesses 29 leave behind rolling depths 32 in the exterior recess 29 of the respective webs 27. The internal borders 33 and 34 create rolling depths 30 within the fillet 5 corresponding to the borders 22.

FIG. 6 shows the situation in a deep rolling machine (not shown) where two deep rolling heads 10 and 23 machine the exterior recesses 29 of two adjacent crankpins 3 and 4 of a crankshaft 1. The work rollers 11 and 12 are opposite one another by 180° in relation to the main rotational axis 35 of the crankshaft 1 Two supporting rollers are opposite each work roller 11 and 12. The supporting rollers are aligned in a support roller head 37. The circumference section 38 of the illustrated fillet 5 which is hatched since it is cut is machined by the border 33 of the interior work roller 11 while the circumference section 39 is machined by the border 34 of the interior work roller 11 on the left part of FIG. 6.

FIG. 7 depicts a situation where only one deep rolling head 10 or 23 is seen. In its axial width 37, the deep rolling head 23 extends beyond the axial width 38 of the bearing seat 36 and its recess 28 of the split pin crankpins 3 and 4. The recess 39 of the fillet 5 is also always rolled when deep rolling the split pin crankpins 3 and 4.

The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. 

1-6. (canceled)
 7. A deep rolling head for deep rolling radii or recesses that limit a bearing seat on a side for main pins and crankpins on crankshafts in motors in vehicles comprising: two disk or ring-shaped and cylindrical work rollers with the same external diameter and almost similar axial width, said two work rollers being parallel and at a mutual distance from one another in a housing of the deep rolling head, said two work rollers mounted so that they can rotate at a common, horizontal rotational axis in the housing of the deep rolling head; and said two work rollers each having a protrusion on their opposite, exterior borders that is peripherally, rounded off, said protrusion increases the external diameter of each work roller by a specified size and simultaneously extends beyond the section near to the edge of the axial width of the work roller.
 8. The deep rolling head according to claim 7, wherein an axial distance of the exterior borders of both work rollers corresponding to the axial width of the bearing seat and the radii that are limiting it on the side or recesses of a main pin or crankpin of the crankshaft.
 9. The deep rolling head according to claim 7, wherein one of the work rollers having a protruding ring flange on one side and the other work roller having a protruding cylindrical pin on one side, the ring flange of one work roller as well as the pin of the other work roller being concentrically aligned to the common rotational axis of both work rollers.
 10. The deep rolling head according to claim 9, wherein the cylindrical pin of one work roller engaging almost free of play into the ring flange of the other work roller in the assembled deep rolling head.
 11. The deep rolling head according to claim 4, wherein both work rollers being connected by screws or pins allowing for detachment, or being permanently adjoined by riveting.
 12. The deep rolling head according to claim 9, wherein the work rollers on an exterior circumference of the ring flange of on of the two work rollers in the housing of the deep rolling head being mounted so that they can rotate. 